The present invention is directed toward methods and apparatuses for supporting microelectronic substrates. Conventional microelectronic device packages typically include a microelectronic substrate mounted on a support member and packaged with an encapsulant. In one conventional arrangement shown in FIG. 1, a microelectronic device package 10 can include a support member 20 having a front surface 21 and a rear surface 22 facing opposite the front surface 21. The support member 20 can also have a slot 23 extending from the front surface 21 to the rear surface 22. A microelectronic substrate 40 (visible through the slot 23) is attached to the rear surface 22, and has wire bond pads 41 that are accessible through the slot 23 for coupling to the support member 20. Accordingly, the support member 20 can include active trace patterns 30, each of which has a wire bond pad 32, a ball bond pad 31, and a connecting trace 33 extending between the wire bond pad 32 and the ball bond pad 31. Each active trace pattern 30 can also include an electroplating trace 34 coupled to an electroplating bus 24 to provide electrically conductive coatings on the active trace pattern 30 during the formation of the support member 20.
In operation, the wire bond pads 32 of the active trace patterns 30 are connected to corresponding wire bond pads 41 of the microelectronic substrate 40 with wire bonds 42. A solder ball (not shown in FIG. 1) can then be disposed on each ball bond pad 31. The wire bonds 42 and the wire bond pads 41 and 32 can then be covered with an encapsulating material for protection, while the solder balls remain exposed. The exposed solder balls can be connected to other devices to provide for communication between those devices and the packaged microelectronic substrate 40.
In order to conform with industry standards, similar device packages 10 are often required to have the same number of solder balls, even if not all the solder balls are required to provide communication with the microelectronic substrate 40. Accordingly, the support member 20 can include inactive trace patterns 50. Each inactive trace pattern 50 can include a ball bond pad 51 that supports a solder ball, and an electroplating trace 54 for electroplating conductive coatings on the inactive trace pattern 50. The inactive trace patterns 50 do not include a wire bond pad 32 or a corresponding connecting trace 33. Accordingly, the inactive trace patterns 50 do not provide electrical communication to or from the microelectronic substrate 40. However, the inactive trace patterns 50 can support solder balls which, together with the solder balls on the active trace patterns 30, define a uniform pattern of solder balls that can be compatible with a variety of devices in which the package 10 is installed and/or tested.
FIG. 2 illustrates a conventional test apparatus 60 for testing device packages such as the package 10 described above with reference to FIG. 1. In one aspect of this arrangement, the test apparatus 60 can include a base 61 that supports the device package 10. An overlying frame 62 secures the package 10 to the base 61. When the package 10 is secured to the base 61, solder balls 25 of the package 10 remain exposed through an opening 65 in the frame 62. A test jig 63 is then aligned with the base 61 such that test contacts 64 of the jig 63 make physical and electrical contact with the solder balls 25 of the package 10. The test jig 63 is then used to test the operational characteristics of the device package 10.
One drawback with the foregoing arrangement is that the test jig 63 can partially or completely dislodge some of the solder balls 25 and/or the trace patterns to which the solder balls 25 are connected. The dislodged solder balls 25 and/or trace patterns can increase the incidence of short circuits in the package 10, and accordingly packages with these defects are typically discarded.